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US2429671A
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Treatment of materials containing tantalum and niobium
Assignee: Individual
•
Filing: 1938-12-02
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Granted: 1947-10-28
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Expires: 1958-12-02
Abstract
No abstract record available.
Inventors
- 👤 Cuvelliez Francois
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:51
CPC Classifications
C; C22; C22B; C22B34/00; C22B34/20; C22B34/24; C01; C01G; C01G33/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-10-27 | 1951-04-28 | 1951-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-10-27 | 1955-04-28 | 1955-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-10-27 | 1959-04-28 | 1959-10-28 | $7700.00 | Window Closed / Lapsed |